VLOOKUP not working properly

NOTE: This thread is a tangential continuation from this one.

I do not know why my VLOOKUP column is only working for 4 cells. I've converted everything to numbers and checked for extra spacing, and I don't know what else to do.

For example, there is no difference between A21 and B31 (except for cell reference)

Formula:

=VLOOKUP(B21,'Rand #'!$A$2:$B$61,2,FALSE)

Formula:

=VLOOKUP(B31,'Rand #'!$A$2:$B$61,2,FALSE)

And yet, A21 yields a "N/A" error, and A31 gives the correct value.

Please see attached sheet.